| | Mount Holly, NC | Belmont, NC | United States |
| Population | 17,315 | 14,442 | 329,725,481 |
| Female Population | 51.7% | 54.4% | 50.5% |
| Male Population | 48.3% | 45.6% | 49.5% |
| Median Age | 37.4 | 35.7 | 38.4 |
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| Population - 2010 | 13,660 | 10,230 | 309,327,143 |
| Population - 2000 | 9,618 | 8,705 | 285,036,114 |
| Population - 1990 | 7,710 | 8,434 | 251,960,433 |
| Pop. 2000 to Now | 70.7% | 45.0% | 15.6% |
| Pop. 1990 to Now | 112.9% | 49.7% | 30.8% |
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| Population Density | 1,595.0 | 1,202.2 | 93.4 |
| Land Area | 10.9 | 12.0 | 3,531,905.4 |
| Water Area | 0.1 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Mount Holly, NC | Belmont, NC | United States |
| Age 0 to 4 | 4.9% | 6.4% | 5.9% |
| Age 5 to 9 | 6.7% | 7.8% | 6.1% |
| Age 10 to 14 | 5.4% | 7.5% | 6.6% |
| Age 15 to 17 | 3.4% | 3.9% | 3.9% |
| Age 18 to 20 | 2.6% | 5.5% | 4.0% |
| Age 21 to 24 | 6.1% | 3.5% | 5.2% |
| Age 25 to 34 | 16.3% | 14.9% | 13.8% |
| Age 35 to 44 | 12.9% | 11.8% | 12.9% |
| Age 45 to 54 | 16.6% | 14.4% | 12.6% |
| Age 55 to 59 | 7.7% | 6.8% | 6.7% |
| Age 60 to 64 | 6.0% | 4.0% | 6.3% |
| Age 65 to 74 | 7.8% | 8.7% | 9.6% |
| Age 75 to 84 | 2.5% | 3.8% | 4.5% |
| Age 85 and over | 1.2% | 1.2% | 1.9% |
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| Race | | | |
| | Mount Holly, NC | Belmont, NC | United States |
| White | 72.6% | 78.2% | 59.4% |
| Black | 15.7% | 10.2% | 12.2% |
| Asian | 5.0% | 3.2% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.3% | 0.4% | 0.4% |
| Two or More Races | 1.7% | 4.9% | 3.2% |
| Hispanic | 4.6% | 3.0% | 18.4% |
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| Marriage & Family | | | |
| | Mount Holly, NC | Belmont, NC | United States |
| Married Population | 52.1% | 48.3% | 49.8% |
| Currently Married | 49.1% | 43.7% | 48.0% |
| Married but Separated | 3.0% | 4.6% | 1.8% |
| Single Population | 47.9% | 51.7% | 50.2% |
| Never Married | 32.8% | 33.9% | 33.8% |
| Divorced | 11.3% | 13.3% | 10.8% |
| Widowed | 3.8% | 4.5% | 5.6% |
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| Household Size | 2.49 | 2.48 | 2.60 |
| Households | 6,950 | 5,523 | 124,010,992 |
| Family Households | 4,658 | 3,310 | 80,755,759 |
| Married couple, w/children | 24.0% | 31.8% | 30.5% |
| Married couple, no children | 44.2% | 39.4% | 42.9% |
| Non Family Households | 2,292 | 2,213 | 43,255,233 |
| Single householder, w/children | 23.7% | 23.0% | 15.8% |
| Single householder, no children | 8.1% | 5.9% | 10.8% |